ci(bonedigger): drop the no-op schedule trigger (#1061)

#981 tracked the decision to stop dispatching the bonedigger lifecycle
reusable workflow for events it does not handle. #1011 dropped the
pull_request trigger; the daily schedule trigger (0 9 * * *) remained as
the same class of no-op: the pinned lifecycle (v1, d530767) defines only
on-issue-opened and on-issue-comment, both guarded on github.event_name
being issues/issue_comment, and HEAD has no schedule jobs either. A
schedule dispatch therefore resolves to a fully skipped run every day.

Remove the schedule block so the trigger list matches exactly what the
reusable workflow handles.

Refs #981

Co-authored-by: unknown <unknown@users.noreply.github.com>

Author: hanthor

.github/workflows/bonedigger.yml

@@ -5,8 +5,6 @@ on:
     types: [opened, labeled, closed]
   issue_comment:
     types: [created]
-  schedule:
-    - cron: '0 9 * * *'
 
 permissions:
   issues: write